I took the front shaft to ron at lunch and he said the slip yoke was pretty wobbly. also mentioned that the front half of the slip yoke (female part) looked t be pretty long for a toyota of that year. weird.

anyways, he's looking at it and will probably have an estimate for a rebuilt one tomorrow i'd guess.

Also, he said with the amount of lift on my truck (ome heavy heavy) the double cardan might not be neccesary.

I took the front shaft to ron at lunch and he said the slip yoke was pretty wobbly. also mentioned that the front half of the slip yoke (female part) looked t be pretty long for a toyota of that year. weird.

anyways, he's looking at it and will probably have an estimate for a rebuilt one tomorrow i'd guess.

Also, he said with the amount of lift on my truck (ome heavy heavy) the double cardan might not be neccesary.

yeah, i got that feeling talking to him.. i am excited to see what he builds, but not too excited about paying to have it done (this is the kind of crap yo ukick yourself for.. getting it done halfass then having to do it again)... but i guess she'll be right this time, which is sweet it will be worth it.. the sliders are farther out than i thought.

i am tempted to take him the rear shaft since the front shaft that was supposedly rebuilt he said was worn out. lets see how that front turns out.i have high hopes!!

yeah, i got that feeling talking to him.. i am excited to see what he builds, but not too excited about paying to have it done (this is the kind of crap yo ukick yourself for.. getting it done halfass then having to do it again)... but i guess she'll be right this time, which is sweet it will be worth it.. the sliders are farther out than i thought.

i am tempted to take him the rear shaft since the front shaft that was supposedly rebuilt he said was worn out. lets see how that front turns out.i have high hopes!!

Ron is very honest and he doesn't price gouge so what you'll get back from him is indeed what needed to be done!

Anyone who needs a driveshaft shop on the South side of town, I can't say enough about Englewood Driveshaft. They are located near Hampden and Broadway. My dad has taken in multiple Toyota shafts. Happy with them each time and for a reasonable price. Usually no charge just to look it over and give them a feel. PM me if you need directions or anything.

"I live in Richmond, CA. I have a rebuilt 1978 FJ40. I love this vehicle and have owned it over 10 years. Bought it off my friend who bought it brand new off the lot in 1978 in New Mexico. It's my peace of mind at night living on the Hayward fault. Over the last 7 years, I've had it customized by a specialty shop in Concord, CA (Chevy V8, power steering, higher suspension, bigger tires). He's extremely talented but we've run into a problem he can't seem to figure out and thus this email. In 4-wheel drive high and low, when you let off the gas there's a horrible vibration noise, but only when you let off the gas and only when you're in 4 wheel drive. It's coming from the front end and Ron has changed out almost everything in an attempt to track it down without any luck. Unfortunately, I'm not a mechanic so I can't really offer him any advice, so I decided to try doing some online research and that's how I found you. If you have any suggestions, it would be most appreciated." Cathy Stonehill

The most likely source of this vibration is an out of phase driveshaft. Both ends of the driveshaft need to be in line with each other. It is common for people to accidently misalign them by 90 degrees if they don't look carefully during reassembly. It is also possible to misalign them by differing amounts if you get careless. The next most likely reason is misalignment of the flanges at each end of the shaft. The faces are supposed to be parallel. Changing of drivetrains, modification of suspension and other similar undertakings can result in inadvertent modification of the relationship between the flanges. You can get away with a small amount of misalignment, on the order of 2-3 degrees. Any more than that causes the type of vibration you mention.

The reason behind these potential causes of vibration is that a u-joint does not transmit the rotation smoothly when it is deflected. The deflection creates a situation where the constant speed that is input to the assembly is changed into a cyclic speeding and slowing scenario. The output from the assembly speeds and then slows twice for each revolution. The greater the deflection, the greater the difference between the fast and slow speed. When all is working as intended, the u-joint assembly at the other end of the shaft receives this pulsing input and changes it back to a smooth output on the other end. For this to happen correctly, the u-joints have to be aligned so that they are trying to pulse in phase with each other. They must also be deflected by the same amount so that the pulse is of the same amount. Any difference in the timing or the size of the pulse creates vibration.

Less likely to produce a severe vibration but a possible source is a very worn pinion bearing (differential) or output bearing (transfer case). A bent or even dented driveshaft can also cause this. But I would look to an out of phase (driveshaft ends) or an out of alignment (flanges) condition.

While I'm thinking about it, an "out of balance" is seldom really the problem. If a driveshaft is straight, as it is supposed to be, it does not need to have weights added to it to "balance it." The purpose of weights is to compensate for slightly less than straight shafts. A shaft that is not straight will vibrate. The weights will dampen this out and offset it due to the vibration they cause themselves. While this makes sense for a factory that is turning out thousands of driveshafts a day, there is no reason that any shaft that is custom made or modified for your rig to need any weights. It is supposed to be straight. Insist on it when you have a shaft made (or lengthened or shortened).

I'm betting on a bad output (t-case) bearing myself, considering mine is more of a growling anyway...